A split-site E3 ligase mechanism enables ZNFX1 to ubiquitinate and cluster single-stranded RNA into ubiquitin-coated nucleoprotein particles
Eukaryotic cells use a multi-layered immune response to combat intracellular pathogens. The ubiquitin ligase ZNFX1 has emerged as a crucial yet little understood player that regulates the immune response while protecting against RNA viruses. Our study unveils the molecular mechanism of ZNFX1, mediated by the joint activity of a helicase serving as a nucleic acid sensor and a non-conventional E3 module featuring a split active site. We demonstrate that single-stranded RNA stimulates E3 activity by fostering dimerization of ZNFX1 subunits that translocate along nucleic acid tracks. Juxtaposed E3 domains complement each other, leading to the ubiquitination of ZNFX1 itself and engaged RNA molecules, while clustering nucleic acids into dense nucleoprotein particles. We show that the E3 ligase activity of ZNFX1 protects cells during an immune response and propose that ubiquitin-coated particles formed by ZNFX1 represent part of an ancient mechanism to regulate both foreign and host RNA in the cell.
Authors
- Eric J. Aird (ORCID: https://orcid.org/0000-0002-4873-042X)
- Julian F. Ehrmann (ORCID: https://orcid.org/0000-0003-2518-5681)
- Luiza Deszcz (ORCID: https://orcid.org/0000-0001-5004-3584)
- R Kurzbauer
- Victoria Faas
- Daniel B. Grabarczyk (ORCID: https://orcid.org/0000-0003-0216-7085)
- Moritz M. Gaidt (ORCID: https://orcid.org/0000-0002-8009-294X)
- Gijs A. Versteeg (ORCID: https://orcid.org/0000-0002-6150-2165)
- Anton Meinhart (ORCID: https://orcid.org/0000-0002-0707-5860)
- Paul C. Kirchgatterer (ORCID: https://orcid.org/0000-0002-5917-0819)
- Josef Penninger (ORCID: https://orcid.org/0000-0002-8194-3777)
- Lukas S. Stelzl (ORCID: https://orcid.org/0000-0002-5348-0277)
- Max J. Kellner (ORCID: https://orcid.org/0000-0002-5404-0628)
- Jacob E. Corn (ORCID: https://orcid.org/0000-0002-7798-5309)
- Ingrid Teßmer (ORCID: https://orcid.org/0000-0002-8353-6315)
- Alexander Schleiffer (ORCID: https://orcid.org/0000-0001-6251-2747)
- Tim Clausen (ORCID: https://orcid.org/0000-0003-1582-6924)
- Lillie Bell
- R. Aggarwal (ORCID: https://orcid.org/0000-0002-7659-1762)
- Vanessa Reznikow
Institutions
- Institute of Molecular Biotechnology (AT)
- Austrian Academy of Sciences (AT)
- Research Institute of Molecular Pathology (AT)
- Johannes Gutenberg University Mainz (DE)
- University of Würzburg (DE)
- Max Perutz Labs (AT)
- ETH Zurich (CH)
- Max Planck Institute of Biophysics (DE)
- Vienna Biocenter (AT)
- Institute of Molecular Biology (DE)
Publication Details
- Journal
- Cell
- Published
- 2025-08-27
- DOI
- https://doi.org/10.1016/j.cell.2025.08.006
- Citations
- 8
- Primary Topic
- RNA modifications and cancer
- Type
- article
- Field-Weighted Citation Impact
- 6.45
Funders
- European Molecular Biology Organization
- Paul G. Allen Frontiers Group
- Deutsche Forschungsgemeinschaft
- Vienna Science and Technology Fund
- Austrian Science Fund
- Österreichische Forschungsförderungsgesellschaft
- H2020 European Research Council
- H2020 Marie Skłodowska-Curie Actions